1. Field of the Invention
The present invention relates to a carpet and a method of manufacture therefor. More specifically, the present invention relates to a carpet and a method of manufacture therefor that are capable of improving sound absorbability and productivity.
2. Description of the Related Art
As a carpet used for a vehicle such as an automobile, a variety of carpets have been developed that provide sound absorbing or insulating functions which insulate noise from outside the vehicle cabin as well as absorb sound within the vehicle cabin.
An example of a carpet according to a related art providing such sound absorbing or insulating functions has been proposed and is shown in FIG. 6. In this example, a carpet 108 is formed by laminating a surface base material layer implanted with a pile yarn 109, a surface latex layer 111 having minute holes, a PE powder layer 112 that serves as an adhesive layer, a sound absorbent layer 113 made from non-woven fabric and an air-impermeable backing material layer 114. As a result, sound from outside the vehicle cabin is blocked out by the backing material layer 114, and at the same time sound from within the vehicle cabin passes through the surface basic material layer 110, the surface latex layer 111 and the PE powder layer 112 and is absorbed in the absorbent non-woven fabric layer 113.
An example of a method of manufacture for the carpet 108 is shown in FIGS. 7A to 7F. In the method employed in this example, a non-woven fabric 115 is made into sheet form by a needle punch 116 (FIG. 7A), which is then heated and hardened to obtain the sound absorbent non-woven fabric layer 113 (FIG. 7B). Meanwhile, the pile yarn 109 is implanted into the surface base material layer 110 using a tufting machine (FIG. 7C), on a reverse side of which, latex 117 is applied and then heated to form the surface latex layer 111 (FIG. 7D). A PE powder 118 is applied to the surface latex layer 111 and then heated to form the PE powder layer 112, and practically simultaneously, the sound absorbent non-woven fabric layer 113 is adhered thereon (FIG. 7E). Finally, a T die laminate process is applied to a reverse side of the sound absorbent non-woven fabric layer 113 to form the backing material layer 114 (FIG. 7F).
As shown in FIG. 8, a carpet according to another related art providing such sound absorbing or insulating functions has been known. As shown, a carpet 100 is formed by laminating a surface material layer 101, an adhesive film layer 102, a sound absorbent non-woven fabric layer 103 and a resin layer 104 (see Patent Document 1 for an example). Within which, the surface material layer 101 includes a base fabric 105, which is implanted with pile yarn 106, and a pre-coated layer 107, which is air-permeable through a pre-coating treatment, and applied on an undersurface of the base fabric 105. Also, the adhesive film layer 102 is air-permeable due to a plurality of minute holes formed by the fiber of the sound absorbent non-woven fabric layer 103. Thus, sound from outside of the vehicle cabin is blocked by the resin layer 104, and at the same time, sound from within the vehicle cabin can pass through the surface material layer 101 and the adhesive film layer 102, and is then absorbed in the sound absorbent non-woven fabric layer 103.
Furthermore, as shown in FIGS. 9A and 9B, a carpet according to yet another related art providing such sound absorbing or insulating functions has been known. As shown, a carpet is formed by laminating a plastic foam sheet 119, a reinforcement base fabric 120 and a fiber assembly sheet 121. From a side of the fiber assembly sheet 121, a pile yarn 122 is implanted through all layers 121, 120 and 119 for penetration. On a reverse side of the fiber assembly sheet 121, an emulsion resin is applied (see Patent Document 2 for an example). Thus, sound from outside the vehicle cabin is blocked by the fiber assembly sheet 121, and at the same time, sound from within the vehicle cabin is absorbed by the plastic foam sheet 119, which serves as a sound absorbing layer.    Patent Document 1: Japanese Patent Application Publication No. JP-A-2005-334435    Patent Document 2: Japanese Patent Application Publication No. JP-A-2004-105458
However, the carpet 108 of the related art involves a large number of production processes (6 processes) and thus a low level of productivity. In addition, its sound absorbability needs to be further improved.
In addition, the carpet 100 of Patent Document 1 has minute holes formed in the adhesive film layer 102 to enable penetration through to the fiber of the sound absorbent non-woven fabric layer 103. However, there is no control over the size, the number, the arrangement or the like of the holes. It is possible to consider solving this by opening holes in the adhesive film layer 102. However, this would result in increased manufacturing processes and thus lower productivity.
Also, referring to the carpet 123 of Patent Document 2, the plastic foam sheet 119 that serves as the sound absorbent layer is exposed on the surface. This means that although sound enters from the surface side, it is discharged before being dampened, which results in an extremely low level of sound absorbability.